How to stay warm in the operating room: a practical guide for staff
To stay warm in the operating room, layer from the skin out within your facility's attire policy: a close-fitting, low-lint base layer under scrubs, a clean warm-up jacket when arms may be covered, and added core warmth such as a thin vest. Cover your head and feet, keep moving between tasks, eat and hydrate, and ask about room temperature between cases.
How cold are operating rooms kept?
ASHRAE Standard 170-2008 sets a design range of 68°F to 75°F (20°C to 24°C) for operating rooms, with humidity limits alongside it. In practice many rooms run near the cool end. A 2023 trial of surgeon cooling vests describes rooms maintained near 20°C, and a 2026 German study measured 20.1°C to 20.7°C in a working room with unidirectional airflow.
At those temperatures, a gowned surgeon under surgical lights may be comfortable while a nurse charting at a workstation, or an anesthesia clinician sitting near the supply airflow, is cold. Knowing that the setting is a deliberate compromise helps you plan clothing instead of waiting for the thermostat to change.
Step 1: Read your facility's attire policy first
Every warmth strategy has to pass your local rules. AORN's Guideline for Surgical Attire made no recommendation on personal clothing worn under scrubs and asked facilities to set policies on fabric type, laundering frequency and laundering method. AORN's 2024 summary adds that the team should decide how much fabric may extend beyond the surgical attire.
That means one hospital may allow a long-sleeve base layer that shows at the wrist while another does not. Check the written policy, or ask your educator, before you invest in new layers.
Step 2: Build a warm, low-lint base layer
OSHA's cold stress guidance describes a three-layer approach, starting with an inner layer of wool, silk or synthetic fabric that moves moisture away from the skin. In the OR, choose a close-fitting base layer that fits cleanly under scrubs and does not shed fibers, since AORN recommends tightly woven, low-linting fabrics for scrub attire.
A thin long-sleeve top and leggings under scrub pants add meaningful warmth with little bulk. Avoid loose knits and anything that pills or sheds.
Step 3: Use a clean warm-up jacket when arms may be covered
AORN describes a long-sleeve scrub jacket, also called a warm-up jacket, as part of surgical attire. The 2019 guideline states that arms may be covered during preoperative patient skin antisepsis and made no recommendation for or against long sleeves at other times, so most facilities leave jacket use to local policy.
Scrub attire, including jackets, should be laundered at a health care-accredited laundry, according to state requirements, or according to CDC recommendations. A facility-laundered jacket usually satisfies policy more easily than a personal jacket washed at home.
Step 4: Add core warmth
When the body cools, it shifts blood flow away from the hands and feet toward the chest and abdomen, as OSHA's guidance explains. Keeping the torso warm therefore supports warmer hands. A thin insulated or heat-reflective vest under or over scrubs is a common option where policy allows.
Some vests have pockets for air-activated warmers or battery heating inserts. Battery devices may need separate approval in clinical areas, so ask before bringing one into a restricted zone.
Position matters too. Anesthesia clinicians often sit close to the supply air stream at the head of the table, so a vest plus a jacket may be needed there even when the same outfit feels too warm for a nurse who is moving around the room.
Step 5: Cover head and feet, and manage your routine
A head covering is already part of surgical attire, and warm, clean socks with closed shoes help your feet. Beyond clothing, small habits add up.
Move when the case allows: stand, stretch and step away from the supply air stream.
Eat before long cases and keep hydrated, since the body needs fuel to produce heat.
Warm your hands between tasks, for example during hand hygiene or with a policy-approved warmer outside the sterile field.
Take breaks in a warmer area and change out of damp clothing promptly.
Between cases, ask the team whether the room temperature can be adjusted within the allowed range.
Which option fits which situation?
The right combination depends on your role and your facility's rules.
| Situation | First choice | Add if still cold |
|---|---|---|
| Circulating, moving often | Base layer plus warm-up jacket | Thin core vest |
| Anesthesia, seated near airflow | Warm-up jacket plus core vest | Warm legs and feet |
| Scrubbed but cold | Base layer under gown | Ask about room setting |
| Between cases or charting | Jacket on, move away from vents | Short warm break |
When is being cold a health question?
Feeling cold in a cool room is normal. Fingers that turn white or blue, persistent numbness, or feeling cold in rooms others find comfortable can have medical causes. Talk to a clinician about symptoms like these rather than relying on extra layers alone.
Key takeaways
Operating rooms are designed for 68°F to 75°F and often run near 20°C, which leaves less active staff cold.
Check your attire policy first; AORN leaves personal under layers and fabric rules to each facility.
Layer from a low-lint base layer to a clean warm-up jacket, then add core warmth.
Habits matter: move, eat, hydrate and step out of the supply air stream when you can.
Frequently asked questions
What should I wear under scrubs to stay warm in the OR?
A close-fitting, low-lint base layer in synthetic, silk or fine wool is the usual choice. Check whether your facility allows sleeves or leggings to show beyond the scrubs, since AORN leaves that decision to each team.
Are warm-up jackets allowed in the operating room?
AORN recognizes the long-sleeve scrub jacket, or warm-up jacket, as part of surgical attire. Most facilities require it to be clean and laundered by an accredited laundry or according to policy.
Why do anesthesia providers get so cold in the OR?
They often sit for long periods near the supply airflow, wear lighter clothing than scrubbed staff and have a lower activity level. Model studies predict more cold discomfort among anesthesia clinicians than among gowned surgeons in the same room.
Can I use hand warmers in the operating room?
Many facilities allow air-activated warmers in pockets outside the sterile field, but policies vary. Never place a warmer directly against skin for long periods, and follow the product's instructions.
Can the OR temperature be changed for staff comfort?
Operating rooms usually have individual temperature controls, and settings can be adjusted within the facility's allowed range. Changes are typically agreed within the team, with patient needs and the surgeon's comfort under the gown both considered.
Related reading
Sources
Environmental Conditions for Operating Rooms (ASHRAE Standard 170-2008 summary), Barton Associates
Surgical Attire, Stethoscopes and Personal Items, AORN Periop Today
Cold Stress Guide, Occupational Safety and Health Administration
One Operating Room, Two Thermal Worlds: Determinants and Limits of Thermal Comfort for Surgical Staff, Atmosphere (MDPI), 2026
Cooling vest improves surgeons' thermal comfort without affecting cognitive performance: a randomised cross-over trial, Occupational and Environmental Medicine, 2023 (PMC)
About HEATJAC. HEATJAC is a thermal architecture company founded by an anesthesiologist. We design patented garment systems that capture, conduct and broaden warmth across the body, and we publish this knowledge hub because the science of staying warm should be public. HEATJAC products are not medical devices and are not intended to diagnose, treat, cure or prevent any disease.